Search Publications
(42355) Typhon Echidna: Scheduling observations for binary orbit determination
Muinonen, K.; Spencer, J. R.; Grundy, W. M. +6 more
We describe a strategy for scheduling astrometric observations to minimize the number required to determine the mutual orbits of binary transneptunian systems. The method is illustrated by application to Hubble Space Telescope observations of (42355) Typhon-Echidna, revealing that Typhon and Echidna orbit one another with a period of 18.971±0.006 …
The Ascraeus Mons fan-shaped deposit: Volcano ice interactions and the climatic implications of cold-based tropical mountain glaciation
Head, James W.; Kadish, Seth J.; Marchant, David R. +1 more
Amazonian-aged fan-shaped deposits extending to the northwest of each of the Tharsis Montes in the Tharsis region on Mars have been interpreted to have originated from mass-wasting, volcanic, tectonic and/or glacial processes. We use new data from MRO, MGS, and Odyssey to characterize these deposits. Building on recent evidence for cold-based glac…
Investigation of water vapor on Mars with PFS/SW of Mars Express
Lellouch, E.; Ignatiev, N. I.; Fouchet, T. +4 more
New insight into the seasonal, diurnal and spatial distribution of water vapor on Mars has been obtained from analyzing the spectra of the short-wavelength channel (SW) of the Planetary Fourier Spectrometer (PFS) onboard Mars Express. The processed dataset, recorded between January 2004 and April 2005, covers the seasons from L=331° of Mars Year 2…
Forced obliquity and moments of inertia of Titan
Nimmo, Francis; Bills, Bruce G.
The obliquity of Titan is small, but certainly non-zero, and may be used to place constraints on Titan's internal structure. The measured gravity coefficients of Titan imply that it is non-hydrostatic and thus the normal Darwin-Radau approach to determining internal structure cannot be applied. However, if the obliquity is assumed to be tidally da…
The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra
Irwin, P. G. J.; Teanby, N. A.; de Kok, R. +9 more
We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12
Moonlets and clumps in Saturn's F ring
Nicholson, Philip D.; Hedman, Matthew M.; Colwell, Joshua E. +2 more
Cassini UVIS star occultations by the F ring detect 13 events ranging from 27 m to 9 km in width. We interpret these structures as likely temporary aggregations of multiple smaller objects, which result from the balance between fragmentation and accretion processes. One of these features was simultaneously observed by VIMS. There is evidence that …
Visible and near infrared spectroscopic investigation of E-type asteroids, including 2867 Steins, a target of the Rosetta mission
Barucci, M. A.; Fornasier, S.; Dotto, E. +1 more
We present the results of a visible spectroscopic survey of igneous asteroids belonging to the small and intriguing E-class, including 2867 Steins, a target of the Rosetta mission. The survey was carried out at the 3.5 m Telescopio Nazionale Galileo (TNG), and at the 3.5 m New Technology Telescope (NTT) of the European Southern Observatory. We obt…
The dust trail of Comet 67P/Churyumov Gerasimenko
Reach, William T.; Kelley, Michael S.; Lien, David J.
We report the detection of Comet 67P/Churyumov-Gerasimenko's dust trail and nucleus in 24 µm Spitzer Space Telescope images taken February 2004. The dust trail is not found in optical Palomar images taken June 2003. Both the optical and infrared images show a distinct neck-line tail structure, offset from the projected orbit of the comet. We…
Detection of C 2HD and the D/H ratio on Titan
Vinatier, Sandrine; Nixon, Conor A.; Jolly, Antoine +8 more
We report here the first detection of mono-deuterated acetylene (acetylene-d1, C 2HD) in Titan's atmosphere from the presence of two of its emission bands at 678 and 519 cm -1 as observed in CIRS spectral averages of nadir and limb observations taken between July 2004 and mid-2007. By using new laboratory spectra for this mol…
Triaxial ellipsoid dimensions and rotational poles of seven asteroids from Lick Observatory adaptive optics images, and of Ceres
Drummond, Jack; Christou, Julian
Seven main belt asteroids, 2 Pallas, 3 Juno, 4 Vesta, 16 Psyche, 87 Sylvia, 324 Bamberga, and 707 Interamnia, were imaged with the adaptive optics system on the 3 m Shane telescope at Lick Observatory in the near infrared, and their triaxial ellipsoid dimensions and rotational poles have been determined with parametric blind deconvolution. In addi…